kapk22
Well-Known Member
- First Name
- Kasey
- Joined
- Apr 19, 2020
- Threads
- 169
- Messages
- 973
- Reaction score
- 433
- Location
- San Antonio Texas
- Vehicle(s)
- 1990 YJ, 2021 JLUR
- Thread starter
- #151
Thank You. The one parts guy at the dealership in California was wrong then.They absolutely are different.
The PCM is a Powertrain Control Module, and it manages everything.
The ECM is the Engine Control Module, and it only manages the engine.
The TCM is the Transmission Control Module, and it only manages the transmission.
In the world I work in, class 8 heavy duty trucks, we have all of the above, plus several others. In today's trucks, depending on the brand you buy, it takes about 22 computers to run one.
Back in the old mechanical days you would put your foot down on the accelerator pedal and it would push a rod that would adjust the carburator and you would begin to move, speed, up, slow down, whatever action you wanted.
Today, you put your foot down on the accelerator pedal, and it moves a potentiometer, which tells the transmission (automatic or manual, just different languages) what you want. The transmission asks the engine for the power, and tells the rear end(s) what's coming. The rear end(s) check with the ABS system to confirm traction state, and prepares to receive the power. If the rear ends don't like what's coming it,/they tell the transmission, and the transmission readjusts its request of the engine ... and so on, and so on ... until all the pieces are happy. Millions upon millions of communications per millisecond.
The PCM, which manages this entire system, doesn't really care though if you, the driver, are happy or not.
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